Printers may have a moving printhead that is driven by a belt and a control system. To accurately determine the location of the printhead across the width of a print zone, an encoder strip is located within the printer. An optical position sensor on the printhead reads the encoder strip as the printhead moves across the print zone and relays position information to a controller. The controller uses the position information, and other information, to determine when to fire ink from the printhead onto the substrate on which printing is to occur.
Over the lifetime of a printer, an encoder strip may become contaminated with aerosol ink artefacts and ink stains such that it is read less reliably by the position sensor and positional accuracy of elements of the printed image may be affected.